Altius recorded 297 priced readings of nonstop business-class round trips from Boston (BOS) to Madrid (MAD) booked 30 days out, across 133 departure dates between 2026-05-20 and 2026-10-05. Observed fares ran from US$2,699 to US$18,685. The lowest fare Altius scored on this window was US$2,999 for a 2026-10-11 departure, seen on 2026-09-11 — IMPRESSIVE at the time, 24.6% below the US$3,977 this route was typically running that day.
A fare can move between our two readings of the same day, most often on the days furthest below typical. Where a day's two readings differ enough to matter, the chart marks that day and both readings can be read separately.